Stoker-operating mechanism



0ct.29, 1929. HTHA HER, JR 1,733,1 i2\ v STOKER'QPERATING MECHANISM Original Filer} 1927 2 Sheets-Shee l is H I 40 a [L 32 i 2 i L F E I n H l 12 20'? if 5.9. i 56 1 23 HHJ J 44 /l/ENTOR ATTO F? NE Patented Oct. 29, 1929 UNITED STATES.

PATENT OFFICE STOKER-OPERATING MECHANISM Original application filed February 1, 1927, Serial No. 165,088. Divided and this application filed January 25, 1928. 'Serial No. 249,266.

Various forms of power actuated mechanisms have been employed heretofore to stoke furnaces, but since the stoker operating l mechanism is necessarily exposed more or less to the dirt and dust of the furnace room, it is important that the mechanism employed be simple in construction and free from small cooperating parts that are likely to be inlation of dirt and dust about the working parts. It is also important that the means employed for operating the grate bars be positively actuated so that movement of the grate bars to and from their stoking position will be insured.

The present invention is therefore directed to stoker operating mechanism that is simple in construction, positive in operation, and which is free from small operating parts that are likely to be injured or rendered inoperative by the dirt and dust of the furnace room.

In accordance with the presentinvention a power shaft is provided which is positively rocked back and forth at any desired speed, and upon the power shaft are loosely mounted one or more power transmitting arms. Associated with each arm is a simple form of locking device adapted to be moved into and out of position to look a particular arm to the shaft to impart the rocking movement of the shaft to such arm, and each locking device is provided with power controlled means for periodically shifting the locking device to and from the arm actuating position. As a result of this construction each arm is positively rocked back and forth at any desired frequency to impart the desired move ment to the mechanism to be operated.

The various features of the invention and novel combination of parts will be best understood from the following description and accompanying drawings which illustrate one good practical form of the invention.

jured or rendered inoperative by the accumu- In the drawings Fig. 1 is a perspective view of the power operating mechanism of the present invention;

Fig. 2 is a side view of the mechanism of Fig. 1 with parts in section;

Fig. 3 is a side view of a power transmitting arm.

Fig. dis a front elevation of the mechanism of Fig.1; and

Fig. 5 is a vertical sectional View through a furnace having the operating mechanism of the present invention in position to periodically raise and lower the grate bars.

The operating mechanism of the present invention is designed more particularly to periodically operate the grate bars of a mechanical stoker, and is therefore shown as mounted upon a furnace in position to operate the grate, but it will be apparent. that this mechanism may be employed for other purposes where a periodic movement is desired.

The power actuated mechanism which will now be described is shown as mounted uponv the front plate 10 of a furnace and the rocking power shaft 11 extends across the front of the furnace and is supported by brackets 12 that extend outwardly from the front plate 10. The shaft 11 may have any desired length depending upon the number of power transmitting arms 13 which are to be operated by this shaft and the distance these arms are spaced apartlengthwise of the shaft. In the construction shown three arms 13 are provided, one for operating each of the three independently operable groups of grate bars shown in Fig. 5, and which will be hereinafter described, but if the furnace is relatively wide it may be provided with additional sets of the grate bars shown in Fig. 5, in which case the shaft 11 will be of sufiicient length to support and operate additional arms 13.

The power shaft 11 is journaled in bearings 14 provided upon the supporting brackets 12 and this shaft is positively rocked back and forth by an arm 15 which is rigidly se cured to the shaft. Rocking movement is imparted to the arm 15 from an electric motor 16 that maybe mounted on a support secured 0 Cir to one side of the furnace wall in an elevated position. This motor operates a series of re ducing gears enclosed in the gear casing 17 and these gears rotate a transversely extending shaft 18 to which is rigidly secured a disk 19. Rocking movement is imparted from the rotating disk 19 to the rocking arm 15 by a connecting rod 20 the upper end of which is journaled upon a pin 21 secured to the disk eccentrically of the driving shaft 18, and the lower end of the connecting rod 20 is fastened to the outer end of the arm .15 by the pin 22. The position of the are other mechanism to be actuated... Each arm 13 in the construction shown is loosely mounted upon the shaft 11 and is held against movement lengthwise of the shaft by a pair of hub members 24 disposed at the opposite sides of the enlarged upper end of the arm 13. These hub members are keyed or other- 'wise' rigidly secured to the power shaft so that the rotative movement of the shaft will serve to rock these hub members, and means is provided for positively locking the power transmitting arm 13 to the hub members 24 to cause the rocking movement of the power shaft to be imparted to said arm.

The locking. means shown consists of a key 25 which is slidably mounted in a slot 26 for-med in the upper portion of the arm 13 as best shown in Fig. 3, and this'key is of suflicient length to extend across the pair of hub members 24, the construction being such that when the power shaft is turned to align the slots 27 formed in each hub member with the slot 26 of the rocking arm, the key 25 may be moved downwardly into the slots '27. The parts are so constructed that long as the'key 25 1s in the elevated POSltlOIl in which it is shown in Fig. 2 the rocking movement imparted to the power shaft 11 and hub members 24 will not be imparted to the arm 13 which is loosely mounted on I the power shaft, but when the key 25 is moved downwardly into the slots 27 formed in the pair of hub members it will positively lock the power transmitting arm 13 to the operating shaft 11 to thereby impart the rocking movement of this shaft to the arm 13.

It, is important that power controlled means be provided for moving the key 25 111130 and out of its lOClZlIlff position, and the key controlling mechanism should be so con structed that it will not release the arm 13 from the power shaft 11 until the arm has been positively moved by the power shaft through a complete stroke. The desirable control of the key 25 is secured, in accordance with the present invention, through the provision of a rocking lever 23 one end of which is pivotally secured at 29 to a bracket 30 which may be bolted or otherwise secured to the furnace front plate 10. This lever 23 is constructed and arranged so that when the same is in its lowered position the outer portion of the lever will rest upon the key 25 with sufiicient force to insert the same into the hub notches 2? when the notches 27 are turned into alignment with the key 25. In most constructions it is desirable that the rocking arm 13 be released from the power shaft 11 after making one complete stroke; that is, after this arm has been rocked from the lefthand position in which it is shown in Fig. 2, to the right-hand position of Fig. 2 in which the second arm is shown, and then back to its original left-hand position. This desired control of the rocking arm 13 is secured by providing the cam operating shaft 31 which extends across the front of the furnace parallel to the power shaft 11 and this cam shaft is provided with as many cams .32 as there are rocking arms 13 upon the power shaft 11. Each rocking lever 28 is normally held in an elevated position by a roller '33 provided at the under face of the lever 28 in position to rest upon the cam 32. The construction is such that when the cam shaft 31 is rotated to turn the notch or depression 34- in the lever supporting cam into engagement with the roller 33 the rocking lever 28 will be lowered momentarily so that it will rest upon the key 25 and move the same to its locking position as the slots 27 are moved into position to receive the key 25. e

The cam operating shaft 31 is journaled in bearings 35 upon the brackets 12, and in the construction shown is rotated with a step-bystep movement. To this end the cam shaft 31 is provided with a ratchet 36 which, in the construction shown, hasthree ratchet teeth spaced 120 apart, and theratchet wheel isv rotated by a pawl 37 which is pivotally mounted. upon an arm 38 which arm is loosely mounted on the shaft 31 for rocking movement. Rocking movement is imparted to the arm 38 from the power shaft 11 by a link 39 one end of which is pivotally. secured to the upper end of the arm 38 and the opposite end of this link is pivotally secured to an arm 40 which is rigidly secured to and projects upwardly from the power shaft 11. From an inspection of Fig. 1 of the drawing it will be seen that the three cams 32 shown have their notches 34; disposed at an angle of to each other and since the cam shaft 31 is rotated through one-third of a complete revolution for each complete rotation of the operating disk 19, one of the three key controlling levers 28 will be lowered each time the rocking arm 15 makes a complete stroke back and forth. As a result of this construction the first power transmitting arm shown in Fig. 1 will be rocked back and forth during one complete rotation of the operating disk 19,

the second arm 13 will be rocked back and forth during the next complete rotation of the disk 19, and a third arm 13 will be rocked back and forth during the third complete rotation of the disk 19 and then this series of operations will be repeated.

It is important that the key 25 be so connected to the key operating lever 28 that the key 25 will not be moved to its inactive position until the rocking arm 13 has completed its stroke and has returned to the left-hand position in which it is shown in Fig. 2. To

long as power is being transmitted from a rocking shaft 11 to an arm 13 to thereby operate one of the rods 44 which actuates a group of grate bars to be described, the key 25 will not be lifted by the elevation of the cam lever 28, since the pressure exerted upon a side face of the key 25 at this time by the power being transmitted through this key will hold. the key in the notches 27, and the elevation of the lever 28 will simply serve to raise the weight 43 to the upper position in which the second weight 43 is shown in Fig. 2 of the drawing. As soon as the arm 13 which is being actuated has completed its movement to the left-hand position in which it is shown in 2. the gripping pressure upon the kev 25 will be released, whereupon the key will be retracted by the pull which the weight 43 exerts upon the chain 41. 'It will be understood that when the arm 13 reaches its grate lowered position to be more fully described, the weight of the grate bars will no longer be supported by the operating mechanism described. since these bars when in their lowered position are supported by their supporting frame and not by the grate actuating rods 44.

The construction just described, whereby the key 25 is permitted to remain in its arm actuating position until the arm 13 has completed its stroke, is found to work extremely satisfactorily, but it may be desirable to proto perform its intended function the bolt" 48 will act upon the projection 49 to move the arm 13 to its grate lowered position.

It will be apparent from the foregoing description of the operating mechanism that the power shaft 11 is positively rocked back and forth so that movement of the same throughout its stroke in both directions is assured, and it therefore follows that as long as the rocking arm 13 is operatively secured to this shaft by its key 25 positive movement of such arm back and forth is assured.

WVhen a cam 32 which normally holds its. lever 28 in an elevated position is rotated to a position to lower its lever through the engagement of the roller 33 with the cam notch 34, the lever will move downwardly under the influence of its weight and that of the ball or weight 43 which the lever supports. This will press the key 25 against the curved face of the hub members 24 and will force the key into the slots 27 when these slots are turned by the movement of the shaft 11 into alignment with the key. Should it be desired for any reason to stop the periodic rocking movement of any one of the arms 13, this may be accomplished by simply moving the proper key 25 by hand entirely out of its guide slot 26 to thereby render the arm 13 controlled by this key inoperative.

The form of operating means shown and described for selectively operating the arms 13 not only permits these arms to be operated in any desired order, through proper location of the notches 34 of the cams 32 with respect to the levers which they areto operate, but constitutes a strong and durable construction, possessing but few parts which are not likely to get out of order, or be rendered inoperative by the accumulation of'the dirt and dust of the furnace room upon the operating parts The operating mechanism so far described is shown as employed to operate successive groups of grate bars, as more fully shown and described in the co-pending application above mentioned. These grate bars 45 are shown as arranged in groups of three and the three bars forming the lowermost group'are raised and lowered by one casting 50 to which each bar 45 is operatively connected by the links 51 and transversely extending rods 52 provided with angularly disposed arms, as fully shown and described in said application. The intermediate group of three grate bars 45 is raised and lowered by a second casting 50 and the third or uppermost group of grate bars 45 is operated by a third casting 50'. To each .of g

the castings 50, 50 and 50 is secured an operating rod 44 the upper end of which is secured to a power transmitting arm 13 in a manner to be described, and the arrangement is such that when a particular power transmitting arm 13 is actuated by the mechanism above described, it will pull the casting which it controls frontwardly to raise the grate bars serve to loosen up the fuel bed so that air may pass through the fuel and will serve also to advance the fuel towards the rear of the fur nace to discharge the ashes upon the clearing grate 53 which may be dumped at will to discharge the ashes into the ashpit 54.

It may be desirable to increase or decrease the distance to which the grate bars are elevated, and this may be readily done, in accordance with the present invention, by pro- 'viding an adjustable connection between the outer end of each operating bar 44 and the rocking arm 13 to which such bar is connected, and in theconstruction shown the outer end of each bar 44 is provided. with a slotted head 55 in which is slidably mounted a block 56. This block is secured to the bifurcated end portion of the arm 13 by a pivot pin or bolt 57 the arrangement being such that the block 56 is pivotally secured to the arm 13 and is slidaoly mounted within the slot formed in the head 55. At the outer end of the head 55 is provided a bolt 58 having the hand wheel 59 for rotating this bolt, and the arrangement is such that if the bolt isturned to advance the same into the head 55 it will serve to clamp the block 56 at thelower end of the slot within the head, in which case the full stroke imparted to the rocking arm 18 will be transmitted to the bar 44,.but if the bolt 58 is backed off a desired distance from the clamping position ust mentioned the block 56 will be permitted to travel some distance along this slot before it actuates the rod 44,

thus reducing the movement imparted to the rod to lift the grate bars 45.

. It will be seen from the foregoing that the operating mechanism herein described is simple in construction and is free from small cooperating parts which are likely to get out of order, and that positive movement of the power transmitting arms back and forth at any desired frequency may be secured.

lVha-t is claimed is 1. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rocking power shaft, a power transmitting arm from its locking position to periodically actuate said arm, and auxiliarymeans for moving said arm to the end of its stroke upon failure of said element to function properly.

2. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including. a rocking shaft, power means for positively rocking the shaft back and forth, a power trans- 'mitting arm loosely mounted on said shaft and operatively connected to said rod, an element for locking said arm to said shaft to positively rock the arm back and forth, and means forautomatically moving said element to and from its locking position to periodically actuate said arm.

3. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rocking power shaft, a power transmitting arm loosely mounted on said shaft and operative ly connected to said rod, a sliding key for locking the arm to said shaft, and means for automatically moving the key to and from its locking position to periodically actuate said arm.

4. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rocking power shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod, a hub rigidly secured to said shaft, a sliding key for lockingthe arm to said hub, and means for automatically moving the key to and from'its locking position to periodically actuate said arm.

5. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rock ing power shaft, a power transmitting arm loosely mounted on saidshaft and operativelyconnected to said rod, a sliding key for locking the arm to said shaft, and means adapted to be operated periodicallyby the actuating means for said shaft to control the actuation of said arm and adapted when in one position to urge the key to its arm locking position and when in a second position to urge the key to its arm releasing position.

6. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rocking power shaft, a power transmitting arm loosely mountedon said shaft and operatively connected to said rod, a sliding key for locking the arm to said shaft, a key actuating lever adapted to rest upon said key when in one position to urge the key to its arm locking position and to he in spaced relatlon to the key when 1n a second positlon, a

yielding connection between said key and lever and operable to urge the key to its inactive position when said lever is in the last mentioned position, and means for periodically shifting said lever.

7. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, mean for shifting said rod in V the direction of its length including a rocking power shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod, a locking element for securing the arm to the shaft to impart the rocking movement of the shaft to the arm, means operable periodically to move the locking element to and from the arm locking position, and a yielding connection between said element and its releasing means and constructed so that it will not move the element to its inactive position until after the rocking force imparted through it to the arm is relieved.

8. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length including a rocking power shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod, a locking element for securing the arm to the shaft to impart the rocking movement of the shaft to the arm, means operable periodically to move the locking'element to and from the arm locking position, and a connection between said locking element and the releasing means and constructed so that the locking element may remain in its active position until after said releasing means has been moved to its releasing position.

9. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length including a rock ing power shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod, a locking element for securing the arm to the shaft to impart the rocking movement of the shaft to the arm, means operable periodically to initiate movement ofsaid element to and from its arm operating position, and a connection between said element and its operating means and constructed to effect the movement of said element only upon completion of the stroke of said arm.

10. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length including a rocking power shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod,'a locking element for securing the arm to the shaft to impart the rocking movement of the shaft to the arm, a lever that is operated periodically to initiate movement of said element to and from its arm actuating position, and a yielding connection between the lever and element to permit relative movement between them.

rocking power shaft, power transmitting:

arms loosely mounted on said shaft and operatively connected to said rods to shift one rod and then another, locking elements operable independently to secure the arms to the shaft to operate said arms, means operable.

in timed relation for moving such elements to and from their active position, and a connection between each element and its con-' trolling means and operable so that the element will not be actuated to release its arm until the latter has completed its stroke.

12. In combination with mechanism adapted to be periodically actuated, operating rods, means for shifting said rods including a rocking power shaft, power transmitting arms loosely mounted on said shaft and operatively connected to said rods to shift one rod and then another, locking elements operable independently to secure the arms to the shaft to operate said arms, comprising sliding keys and cooperating notches, means operable periodically to shift said keys, and a connection between each key and its operating means for permitting relative movement between a key and its operating means and said connection being constructed to release a key only upon completion of the stroke of the arm controlled by such key.

13. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length, including a rocking shaft, a power transmitting arm loosely mounted on said shaft and operatively connected to said rod, a hub rigidly secured to said shaft andprovided with a key receiving opening, a key mounted upon said arm for sliding movement into and out of said opening and adapted to lock the arm to said shaft, a lever movable into and out of position to rest on said key and urge it to its locking position, power actuated means for periodically raising and lowering said lever, and a yielding connection between said lever and key and adapted to retract the key when said lever is raised. I

14. In combination with mechanism adapted to be periodically actuated, an operating rod therefor, means for shifting said rod in the direction of its length including a rock ing power shaft, a power transmitting arm loosely mounted on said shaft and operativemoved into and out of position to lock the arm to said shaft to actuate said arm, a cam controlled lever adapted to move the key to and from its operative position, and a cam adapted to be rotated from said power shaft by a step-by-step movement and operable to shift said lever to control the position of said key.

15. In combination with mechanism adapted to be periodically actuated, operating rods, means for shifting said rods, including a rocking power shaft, power transmitting arms loosely mounted on said shaftand operatively connected to said rods, independent- 1y operable keys for locking the different arms to the power shaft to rock said arms, a cam controlled lever for each of said keys, a cam shaft operated from said power shaft, and cams upon said cam shaft and positioned to periodically shift said levers to control the position of said keys.

In testimony whereof, I have signed my name to this specification.

GEORGE H. THACHER, JR. 

